In a vehicle such as an automobile, in order to contribute to the assistance of driving and the reduction of accidents, a technique for recognizing and detecting the presence of a peripheral object around a vehicle has been studied. For example, as a technique using the light-section method utilizing slit light, Japanese Patent Application Laid-Open Publication No. 2011-7711 (Patent Document 1) describes a three-dimensional shape measuring apparatus which includes a light source array, a camera that images a monitoring region, and an image recognizing section, and measures the shape of a solid object around a vehicle by the light-section method.
In the technique described in Patent Document 1, light emitted from the light source array is regarded as pseudo slit light having an irradiation pattern that includes a line segment obtained by connecting light source centers of lights emitted from respective light sources. In the image recognizing section, a distance at an irradiation position on a solid object from the camera is calculated according to the triangulation principle based on a difference between the irradiation pattern and information of the irradiation position of the pseudo slit light estimated on the basis of luminance data of respective pixel lines from image data imaged with respect to the monitoring region irradiated with the pseudo slit light.